Americans are suckers for their pets, but those furry (or scaly or feathery) companions do a lot of damage to the environment. One of the biggest problems is waste. The country's 73 million dogs produce about 10 million tons of poo each year, while our 90 million cats cause about two million tons of cat litter to wind up in landfills. Add to that all the discarded plastic toys, the packaging for dog treats and food, and all the other accessories loving owners buy, and that cute doggy in the window starts to look like an environmental disaster. But there is good news: A whole cottage industry has sprouted up to help you green your pet care practices around the house. Here are a few of the more notable selections.